Self-assembly process for Die-To-Wafer technology

Die to wafer direct bonding is a perfect technique to reach both flexibility, performance and miniaturization of system integration. High throughput and die alignment performances are then requested to increase interconnections density.
“Self-assembly” process is an excellent candidate to push forward the alignment limits as published by CEA-Leti at IEEE ECTC 2019 and 2022. This process consists in using capillary forces generated by a liquid droplet dispensed at the bonding interface to self-align a die on its receiving site.
This year, thanks to a collaboration with Intel, a major breakthrough was reached with a collective bonding of 40 dies aligned at 500 nm 3σ. This confirms the potential of this process to combine advantages of die-to-wafer hybrid bonding and high throughput. This technology enlightens a path for low-cost, high-performance heterogeneous integration.